It is known to coat a siliceous substrate with a silicon containing layer. For example, WO 9908784 discloses a method of treating, a solid material to make it hydrophobic.
Another method of coating a siliceous substrate with a silicon layer is disclosed in PCT/BE00/00033.
The content of these two documents are incorporated herein by reference in their entirety.
It has already been proposed to treat the siliceous substrate with HF (hydrofluorhydric acid) before applying the coating.
It has now been discovered that by making various preliminary treatments, as described hereinafter, it was possible to increase drastically the chemical bonds of the silicon layer with the substrate as well as silicon bounds within the layer.
The invention relates to a process for coating at least a portion of a face of a siliceous substrate with a silicon containing layer.
The process comprises at least the following steps:
a treatment step, in which at least the portion of the face of the siliceous substrate is treated with a composition containing at least one biocide, and
at least the portion of the face of the siliceous substrate is then reacted with a reactive composition for forming a silicon containing layer that is chemically bound to the siliceous substrate.
For example, no drying step is required when applying an amino silane-containing composition on the siliceous substrate.
The reaction with the reactive composition is advantageously carried out at least 10 seconds after the beginning of the treatment step with the biocide containing composition. Preferably, the reaction with the reactive composition is advantageously carried out at least 30 seconds after the beginning of treatment step with the biocide containing composition. For example, the reaction with the reactive composition is advantageously carried out 45 seconds, 1 minute, 2 minutes, 5 minutes, 10 minutes, 20 minutes after the beginning of the treatment step with the biocide-containing composition. Often a time of less than 10 minutes between the beginning of the treatment step and the reaction step is sufficient for obtaining the excellent properties of the coating, as described hereinafter. For example, the drying step (when necessary or desired) of the treated substrate was carried out less than 10 minutes after the beginning of the reaction with the reactive composition.
Advantageously, the biocide composition is selected from the group consisting of aqueous compositions, solvent-containing compositions, alcohol-containing compositions and mixtures thereof. Possible solvents are: organic solvents, such as methanol, ethanol, isopropanol, benzene, dichloro ethane, etc. and mixtures thereof, including with water. However aqueous compositions are preferred for safety reasons.
According to an embodiment, the portion treated with a biocide-containing composition is at least partly washed before being contacted with the reactive composition. The washing step can be carried out by using water, preferably pyrogen free water, solvent, solvent containing compositions, polishing slurries, etc.
Preferably, the portion treated with a biocide containing composition is at least partly dried before being contacted with the reactive composition.
Most preferably, the portion treated with a biocide containing composition is at least partly treated with a means for removing water present on said portion. This water removal can be carried out by a solvent washing (for example by spraying an organic solvent on the treated portion, by dipping the portion in a bath containing one or more organic solvents, etc), by a mechanical removal (wiper, absorbent means, etc), by a low pressure for evaporating the water, by using a gas flow (for example having a low water content, such dried air, the gas having a temperature from 20xc2x0 C. up to 150xc2x0 C., or possibly more, and the gas being advantageously without, or substantially without, solid particles or dusts).
Preferably, the water removal is carried out by a washing step with an organic solvent, the solvent being most preferably a solvent suitable when coating the siliceous support or substrate with the reactive composition for applying a silicon containing layer, for example a solvent used in the composition containing the reactive for forming the silicon containing layer.
According to a preferred embodiment, the process comprises at least the following steps
a treatment step, in which at least the portion of the face of the siliceous substrate is treated with an aqueous composition containing at least one biocide;
preferably, at least the treated portion is washed;
a drying step, in which the (preferably washed) portion is at least partly dried, and
at least the dried portion is reacted with a reactive composition for forming a silicon containing layer chemically bound to the siliceous substrate.
Advantageously, the treated portion layer is washed with an aqueous liquid composition and is dried so that substantially no water remains on the portion of the face to be reacted with the reactive composition. Preferably, the treated portion is free of water before applying the reactive composition for making a silicon containing layer chemically bound to the siliceous substrate.
According to an embodiment, the treated portion layer is washed with an aqueous liquid composition and is dried so that substantially no water remains on the portion of the face to be reacted with the reactive composition. The drying is at least partly carried out by a mechanical removal of the liquid present on said portion.
Preferably, the drying is at least carried out by relative movement of a water absorbing support on the portion of the face.
According to an embodiment, the aqueous composition contains an effective amount of at least a biocide for ensuring an activation of the portion of the face when reacting the portion with the reactive silicon containing composition. In some case, it seems that the use of an aqueous biocide solution with a low biocide content (such as lower than 2% by weight, advantageously lower than 1% by weight, preferably lower than 0.5% by weight) or a high biocide content (higher than 10% by weight) gives the best activation of the siliceous substrate for obtaining an excellent adhesion of the siliceous substrate. However, it has been observed in examples that the use of aqueous biocide solution or liquid composition gives the best adhesion properties of the silicon containing layer on the siliceous substrate.
According to an embodiment, the portion of the face is at least treated with a composition containing at least one metal ion before reacting the portion of the face of the siliceous substrate with the reactive silicon containing composition.
Preferably, at least one of the metal ion is selected from the group consisting of copper, silver, gold, platinum, zinc, magnesium, calcium, sodium, cadmium, rhodium, palladium, salts and mixtures thereof.
Most preferably, the portion of the face is treated with at least a biocide in the presence of a metal ion. The presence of the metal ion, such as Cu++, improves the biocide properties of the biocide solution, but also increase the stability of the solution, thus ensuring an even treatment of the surface. For example, at least one of the metal ions is selected from the group consisting of copper, silver, gold, platinum, zinc, magnesium, calcium, sodium, cadmium, rhodium, palladium, salts and mixtures thereof. The solution applied on the glass sheet has, for example, a metal content of less than 0.5%, advantageously less than 0.1% (such as 500 ppm, 300 ppm), preferably less than 0.01% (such as 100 ppm, 80 ppm, 50 ppm, 20 ppm, 10 ppm) or even in some case less.
Other stabilizing agents can also been used. Therefore, according to an embodiment, the portion of the face is treated with at least a biocide in the presence of at least an effective amount of a stabilizing agent.
According to a preferred embodiment, the portion of the face is treated
with a (preferably aqueous) solution containing biocide in an effective amount for ensuring a bactericidal activity, and/or
with a (preferably aqueous) solution containing biocide in an effective amount for ensuring a microbiocidal activity and/or
with a (preferably aqueous) solution containing biocide in an effective amount for ensuring an antifungal activity and/or
with a (preferably aqueous) solution containing biocide in an effective amount for ensuring an anti algae activity and/or
with a (preferably aqueous) solution containing biocide in an effective amount for ensuring an antifouling activity.
It seems also to be advantageous for the stability of the biocide composition, that the (preferably aqueous) solution containing biocide contains less than 5% by weight of halogenated compounds.
According to possible embodiments, at least one biocide present in the composition is selected from the group consisting of thiazole compounds and their derivatives, isothiasole compound and their derivative, isothiazoline compounds and their derivative, ammonium and their derivative, phosphonium and their derivatives, ammonium-phosphonium compounds and their derivatives, betaine, amido betaine and their derivatives, and mixtures thereof. The biocide can also be the product of the reaction of a biocide with a surfactant, such as a non ionic surfactant.
Preferably, the reactive composition contains reactive silicon-containing reagent bound to at least one fluorine atom, such as a fluoro silane compound, especially those disclosed in PCT/BE00/00033.
The treatment step can be carried out at a temperature comprised between 0xc2x0 C. and the boiling point of the biocide-containing composition. Advantageously, the treatment step is carried out at a temperature comprised between 30xc2x0 C. and the boiling point of the biocide containing composition.
Preferred biocides are selected, from the group consisting of isothiazolone, derivatives thereof, compounds having a isothiazolone functions, 3-isothiazolone compound, 5-chloro-2-methyl-3-isothiazolone, 1-methyl-3,5,7-triaza-1-azoniatricyclo (3.3.1.1) deoane chloride, 4,5-dichloro-2-octyl-3isothiazolone, 2-bromo-2-nitropropanediol, 5-bromo-5-nitro dioxane, thiocyanomethylthiobenzothiazole, 4,5-dichloro-2-octyl-3-isothiazolone and 2n-octyl-3-isothiazolone, tetrachloroisophalonitrile, 1,2-benzisothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, 5-chloro-2-methyl-4isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 4-(2-nitrobutyl)morpholine, beta-nitrostyrene (xe2x80x9cNSxe2x80x9d), beta-bromo-beta-nitrostyrene (xe2x80x9cBNSxe2x80x9d), methylehloro/isothiazolone (xe2x80x9cIZNxe2x80x9d), methylenebisthiocyanate (xe2x80x9cMBTxe2x80x9d), 2,2dibrortmo-3-nitrilopropionamide (xe2x80x9cDBNPAxe2x80x9d), 2-bromo-2-brornomethyl-glutaronitrile (xe2x80x9cBBMGNxe2x80x9d), alkyldimethylbenzylammoniutn chloride (xe2x80x9cADBACxe2x80x9d), and beta-tiitrovinyl furan (xe2x80x9cNVFxe2x80x9d), 2-methyl-3-isothiazolone, methylene bisthiocyanatc:, p-tolyldiiodotnethyl sulfone, 2-methylthio-4-tertbutylarnino-6-cyclopropylamino-s-tiiazine, N,N-dimethyl-Nxe2x80x2-phenyl-(Nxe2x80x2fluorodiehloromethylthio)sulfainide, antibiotics, sulfamides, tetracycline, isothiazolone derivatives, N-(cyclo)alkyl-isothiazolone, benzisothiazolin-3-one, etc. and their mixtures.
Other examples of possible biocides which can be possibly mixed with one or more biocides listed here above are:
Bicyclic oxazolidoines and their mixtures, amine-based bactericide, polyacrolein copolymer, 4,4-dinethyloxazolidine, 2((hydroxymethyl)-amino) ethanol, mixtures of 1,2-benzisothiazolone-3-one with one or more amines,.tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazitie-2-thione. 1.2-benzisothiazolin-3-one, tetrachloroisophthalonitrile, N-cyclopropyl-N-(1,1-dimethylethyl)-6-(methylthio)-1,3;5-triazine-2,4-diamine, mixtures of N-cyclopropyl-N-(1,1-dimethylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine with tetrachloroisophthalonitrile, mixtures of tetrachloroisophthalonitrile with 3-iodo-2-propynylbutyl carbamate, N-(trichloromethylthio)-phthalimide, 3iodo-2-propynylbutyl carbamate, tetrachloroisophthalonitrile, and their mixture.
In some specific advantageous embodiments, the treatment step is carried out in the presence of at least one free-radical scavenger. Examples of free-radical scavengers are: 3,3-thiodipropionic acid, L-ascorbic acid, D-ascorbic acid, furnaric acid, diethylhydroxylaniine, glutaraldehyde, butyraldehyde, L-tartaric acid, 4-methoxyphenol, propyl gallate and mixtures thereof. The solution to be applied on the glass sheet contains, for example, less than 10% by weight of free-radical scavenger(s), advantageously less than 5%, for example 4%, 3%, 2%, 1%, and preferably less than the biocide active agent content.
According to a specific embodiments, the biocide composition is selected from the group consisting of biocide composition containing at least one surfactant, biocide composition containing at least a biocide bound to a surfactant, biocide composition containing at least one surfactant and an acid, a biocide composition containing at least an acid and at least a biocide bound to a surfactant, a biocide composition containing at least a metal and at least one surfactant, a biocide composition containing at least a metal and at least a biocide bound to a surfactant, a biocide composition containing at least one surfactant, a metal and an acid, a biocide composition containing at least an acid, at least a metal and at least a biocide bound to a surfactant, and mixtures thereof.
The surfactant can be a cationic surfactant, an anionic surfactant, a zwitterionic or amphoteric surfactant or a non-ionic surfactant, or a surfactant having two different moieties, or a mixtures of different surfactants. Non-ionic surfactants are preferred, such as alkanolamides, alkoxylated alcohols, amine oxides, block polymers, castor oil derivatives, ethoxylated amides, ethoxylated amines, ethoxylated and/or alkoxylated alkyl phenols, ethoxylated fatty acids, fatty esters, fluorocarbon based surfactants, glycerol and polycerol esters and their derivatives, glycol, polyglyeol esters, polyoxyethylene glycols, lanolin based derivatives, pentaerythritol derivatives, phytosterol and cholesterol derivatives, siloxanes, sorbitan derivatives, sucrose esters and polyglycosides derivatives, tail oil and rosin derivatives, etc. and mixtures thereof. Specific examples are acetamide monoethanolamide, C12-C19 alkyl amido propyl amine oxide, alkanolamide (such as coconut and, linoleic), alkoxylated alkanolamides, cocamide diethanolamide; cocamide monoethanolamide, coco diethanolamide, cocomonoethanolamide, coconut diethanolamide, alcohol alkoxylate, alkoxylated cetyl ether, alkoxylates, alkyl alcohol polypropylene glycol ether, fatty alcohol alkoxylate (for example with 2 to 12 propylene oxide groups), C 12-C 14 fatty alcohol with 2 to 10 ethylene oxide groups and/or 3 to 8 propylene oxide groups, lauramine oxide, myristamine oxide, octamine oxide, tearyl amine oxide, palmitamine oxide, Block Ethylenpoxide/propyleneoxide copolymer, ethoxylated natural oils and fats, ethoxylated triglycei-ides, fatty acid mono and diesters, polyoxyethylene castor oil, polyoxyethylene castor oil ether, ethoxylated alcohols (with 2 to 20 ethylene oxide groups and/or propyleneoxide groups), fatty amine ethoxylated, alkyl phenol ethoxylated, alkyl phenol polyglycol ether (with 2 to 8 ethylene oxide groups and/or propylene oxide groups), fatty acid polyethylene glycol ester, disteaiyl phthalate, butyl stearate, eoco caprilate, diisopropyl sebacate, etc.
The acid is for example a mineral acid (HCI, H2SO4, etc,), an organic acid (citric acid, formic acid, glycolic acid, etc.), and mixtures thereof. The pH of the composition is for example comprised between 0.5 and 10, advantageously between 3 and 9, such as between 5 and 8.5. The acid content of the composition is for example such that after dilution with water and/or solvent(s), the pH is comprised between 1 and 9.
The surfactant content of the biocide composition or blend is for example comprised between 0.01% and 30% by weight, for example 0.1%, 0.2%, 0.5%, 0.8%,1.0%,5%,10%,20%.
The weight ratio surfactant/biocide is for example comprised between 0.5 and 1000, advantageously between 1 and 500, and preferably between 10 and 200, such as 20,50, 70, 100, 125, 150.
The composition may also contain one or more buffer, if necessary.